Tag: GIS

Today, I was working with a very large shapefile (1GB+), and I needed to parse it into several smaller shapefiles based on attributes from a specific field.

There are various methods to doing this. The most time consuming would be to use ‘Select by Attribute’ for each individual attribute and simply export these features manually. This is simple, but takes a long time.

I didn’t have time to do this, so rather than use ModelBuilder I searched and fortunately found a script for ArcToolbox that automated this process: Split Layer By Attributes (authored by Dan Patterson).

Script summary:

Splits a layer according to attributes within the selected field producing a separate shapefile for common attributes.

If the FID or some other unique ID field is used, you can effectively produce separate shapefiles for each feature. If you are using a decimal field with a scale of 0 or an integer field or a string field, you can have one or more features in the output shapefile. Date fields need to be converted to a string field and integer fields should contain positive numbers

The selected field is queried for unique conditions. If a prior selection exists, then only those records are queried. The unique values found in the field (or selection within) are used to partition the input layer into the output layers.

4 Steps:

1. Select the input layer.
2. Select the input field.
3. Tpe an optional output filename (the default is the layer name with the select attribute appended to it.
4. Select the output folder.

Viola. The script spits out separate shapefiles for each different attribute within the selected field.

Since I was working with an enormous shapefile to begin with, the process took a few hours.

Esri further expands access to its ArcGIS software with the addition of a statewide license for New York and its 2.7 million K-12 students.

Now, about a third of all American K-12 students has access to ArcGIS. Amazing. This is definitely one way to increase teaching and learning geography in schools. The map above shows other states and school districts that have K-12 ArcGIS licenses.

Watching Caught Mapping (1940) makes me extremely appreciative of technology like GPS and software like GIS in modern cartography. While we still can’t really get away from field work to gather actual and reliable updated road information, I think computers have made physically updating and producing maps less laborious.

As for those driving duos who braved 115 degree heat to obtain up-to-date road information, you were truly road warriors.

As such, Makai recently releasedMakai Voyager; an advanced 3D/4D visualization platform that uses time-varying and complex geospatial data such as terrain imagery, elevation, LIDAR, volumetric and flow data to better visualize and analyze large environmental simulations. The above image is one example of what using Makai Voyager can accomplish.

Makai Voyager is much more advanced than the typical Geographic Information System (GIS) by ESRI. By being able to utilize existing advanced 3D geospatial data, analysts and planners can better display and interpret proposed changes to the built and natural environments for stakeholders, elected officials, and residents.

While representing the next stages of site analysis, my biggest reservation about Makai Voyager and similar software is that it still seems out of reach from most small budget communities, educational institutions, and nonprofit organizations. For instance, Makai does not even offer a pricing guide on its website, and instead it directs interested parties toward its contact page. The only reason some of these organizations even have ArcGIS capabilities is because ESRI offers generous grants (even if to prevent these organizations from going toward open source solutions like GRASS GIS, Quantum GIS, or SAGA GIS). Otherwise, big firms are the only organizations that can afford it.